@mr-att.bsky.socialwill be the lead moderator of this #ESHREjc – thank you Attilio, the floor is yours 😊

Housekeeping essentials 👇
1. Use the hashtag #ESHREjc in all your posts
2. The #ESHREjc will take place over the weekend starting now until tomorrow 28 March 17.00 CET 🕔
3. Please always comment in the thread of the questions (they will be identified with Q1, Q2, …)

We’d also like to welcome our experts
@prof-lotti.bsky.social
@smdsresearch.bsky.social
@drdanielmarcu.bsky.social
Monica Vazquez-Levin Luca Boeri

#ESHREjc

Welcome to this month's #ESHREjc moderators 🙌 Have fun!
@mr-att.bsky.social
@juanjo-fraire.bsky.social
@gliperis.bsky.social
@ribeirosara.bsky.social
@dkalaitzopoulos.bsky.social
@fabrizzio-horta.bsky.social
@noemisalmeri.bsky.social
@omarammar.bsky.social

🔥 Thank you everyone for attending the #ESHREjc and the first one hosted on Bluesky

Many thanks to our experts for the insightful discussion on the multifaceted role of the oocyte cortex @rvassena.bsky.social @paolavigano.bsky.social

And the # ESHREjc team 💫

Until next time! 👋🏻

What have we been discussing during the #ESHREjc discussion on the oocyte cortex? Have a look at the summaries starting with q1 on its role in maturation 👇🏻

Until next time! 👋🏻

@omarammar.bsky.social @mr-att.bsky.social @noemisalmeri.bsky.social @juanjo-fraire.bsky.social @dkalaitzopoulos.bsky.social @ribeirosara.bsky.social

Almost over for this session of the #ESHREjc ⏰

Summary for #Q2 👇🏼
@eshre.bsky.social

Here’s the summary for Q1 on structural components of the oocyte cortex and GV to MII remodeling #ESHREJC @eshre.bsky.social

Technically a bit difficult! From which follicular stage the testing should be initiated? From primordial? Or once we have more cumulus layers? #eshrejc

To test cortical stiffness is easy and can be done before icsi for example. Measuring young’s modulus by poking the cortex. This could be then correlated with tissue stiffness and further development of the oocyte/embryo. #eshrejc

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Q3. Coticchio et al suggest cortical properties (stiffness, viscoelasticity) could be biomarkers of oocyte developmental competence. Which technologies 🧫🔬🤖could realistically be applied in an IVF lab 👩🏻‍🔬 to measure cortex mechanics and what are the major barriers to clinical 🧑🏻‍⚕️ translation? #ESHREjc

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Q4:Given that the cortex is a part of the interface between the oocyte and cumulus cells, how might abnormalities in the follicular environment alter cortical signaling or architecture, and how could these changes be detected through non-invasive follicular fluid or cumulus cell biomarkers?
#ESHREjc

In mouse, these fragments track poorer progression and lower blastocyst quality/cell number. In humans, fragmentation correlates with poorer prognosis, but the mechanistic link is still a gap. High scale perturbation/imaging is needed. #ESHREjc

Cell fragmentation in mouse preimplantation embryos induced by ectopic activation of the polar body extrusion pathway - PubMed Cell fragmentation is commonly observed in human preimplantation embryos and is associated with poor prognosis during assisted reproductive technology (ART) procedures. However, the mechanisms leading to cell fragmentation remain largely unknown. Here, light sheet microscopy imaging of mouse embryos …

Data so far suggest embryo fragmentation can arise de novo during early cleavages: mitotic chromosome segregation problems keep DNA near the cortex long enough to trigger ectopic actomyosin contractions, essentially a misfired “polar body–like” response. #ESHREjc

pubmed.ncbi.nlm.nih.gov/37427462/

Q2: The paper proposed that cortical dysregulation can lead to blastomeri fragmentation and reduced blastocyst quality. What are the proposed mechanisms by which ectopic chromosomal signaling or cortical instability leads to abnormal cleavage patterns in early embryos? #ESHREjc

What’s your preferred readout of this switch in human oocytes: PB2 kinetics, PN centration, or cortex stiffness? #eshrejc

Exactly and the testable point is causality: chromatin proximity breaks symmetry (Cdc42/Ran cues), Arp2/3 builds the polar domain, and spatially restricted myosin-II then converts that polarity into mechanics (spindle rotation + PB extrusion) #ESHREjc

chromatin→cortex axis is likely multi-step: chromatin proximity builds a Ran-GTP/Cdc42 polarity cue, and Fyn may gate/amplify local outputs. Downstream suspects include Cdc42–N/WASP→Arp2/3, formins (mDia), pERM, and myosin-II via MRCK/ROCK. #ESHREjc

Mouse gives mechanistic resolution, but human validation is essential given cortical thickness/stiffness differences. Key question is whether the logic (polarity modules + spatially distinct myosin pools) is conserved, even if parameters shift. Any human time-lapse/biomech data? #eshrejc

Myosin-II in the oocyte cortex isn’t a one thing. distinct cortical pools (eg, a polarized ring vs the cytokinetic furrow) are wired to different upstream kinases. So “myosin inhibition” can uncouple polarity from mechanics, giving distinct maturation phenotypes. #ESHREjc

Yes, distinct phenotypes make sense cuz Arp2/3 and myosin-II sit in different control layers. Arp2/3 shapes cortical architecture + actin flows that establish/maintain polarity and cap organization, while myosin-II executes stage-specific force generation needed for rotation/cytokinesis. #eshrejc

Yes, distinct phenotypes make sense cuz Arp2/3 and myosin-II sit in different control layers. Arp2/3 shapes cortical architecture + actin flows that establish/maintain polarity and cap organization, while myosin-II executes stage-specific force generation needed for rotation/cytokinesis. #eshrejc

Internet issue not a skill issue 😭🤣 #eshrejc

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The discussion is open for the next 24h until 17:00 CET tomorrow Saturday

Join the discussion 💫

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Housekeeping rules

Always use the #ESHREjc for all relevant discussion points

The discussion will be moderated by the #ESHREjc team:

@juanjo-fraire.bsky.social
@omarammar.bsky.social
@noemisalmeri.bsky.social
@ribeirosara.bsky.social
@mr-att.bsky.social
@dkalaitzopoulos.bsky.social
@fabrizzio-horta.bsky.social

Q1. How do the structural components of the oocyte cortex (e.g., actin, myosin-!, pERM, Arp2/3, Fyn kinases) dynamically remodel during the transitions from GV to MIl and how do these changes mechanistically support spindle positioning and polar body extrusion? #ESHREjc

Housekeeping essentials 👇
1. Use the hashtag #ESHREjc in all your posts
2. The #ESHREjc will take place over the weekend starting now until tomorrow 31 January 17.00 CET 🕔
3. Please always comment in the thread of the questions (they will be identified with Q1, Q2, …)

Welcome to this month's #ESHREjc moderators 🙌 Have fun!

@gliperis.bsky.social
@noemisalmeri.bsky.social
@omarammar.bsky.social
@mr-att.bsky.social
@juanjo-fraire.bsky.social
@dkalaitzopoulos.bsky.social
@ribeirosara.bsky.social
@fabrizzio-horta.bsky.social